CHEVROLET TRUCK BATTERY PROBLEM

1990 Chevrolet Truck • 73,130 miles

Mr drivers door didn't get shut all the way, and resulted in a very weak battery ( inside lights ). After charging the battery, and after warming it up, it doesn't shut down when I turn off the ignition, the volt meter drops but the engine keeps right on running, responding to the throttle, et. I finally got it to shut down by continued messing with the key ( on-off-on-off etc ). Got a clue? 1990 SS 454. Stock. TBI.